1. Field of the Invention
The invention relates to a bone screw and a bone screw fixation system, especially to a bone screw fixation system applicable in percutaneous invasive vertebrae treatment.
2. Description of the Related Art
Minimally invasive surgeries of fixation systems are used in treating vertebrae. Since the wounds are small, such surgeries can largely reduce the damage to the portions under treatment and the neighboring tissues, can enhance the safety of surgeries, and can decrease healing and recovery time. For accurate positioning and alignment of the fixation system, a bone screw of the fixation system is typically provided with a positioning casing. Thus, the bone screw of the fixation system can be positioned and aligned from the outside of a human body while performing the surgery.
The conventional bone screw fixation system needs a separate aligning device to align the bone screw during insertion of the bone screw into bone. The separate aligning device is rather complicated and/or has multiple components, which results in inconvenience and even requires a wound with a larger width or length during operation. Therefore, there is a need to develop a rather simple and convenient bone screw fixation system. Further, more than one bone screw is inserted into a patient's vertebrae. A bone screw fixation system that reduces the number of operation steps and/or operation time is also desirable.